Initial work on chaining Exporter implementations

src/Util/Exporter/DefaultExporter.php

@@ -23,6 +23,11 @@ public function __construct()
         $this->exporter = new ExporterImplementation;
     }
 
+    public function handles(mixed $value): true
+    {
+        return true;
+    }
+
     public function export(mixed $value): string
     {
         return $this->exporter->export($value);

src/Util/Exporter/Exporter.php

@@ -14,5 +14,7 @@
  */
 interface Exporter
 {
+    public function handles(mixed $value): bool;
+
     public function export(mixed $value): string;
 }

src/Util/Exporter/ExporterChain.php

@@ -0,0 +1,60 @@
+<?php declare(strict_types=1);
+/*
+ * This file is part of PHPUnit.
+ *
+ * (c) Sebastian Bergmann <sebastian@phpunit.de>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+namespace PHPUnit\Util;
+
+use function assert;
+
+/**
+ * @internal This class is not covered by the backward compatibility promise for PHPUnit
+ */
+final readonly class ExporterChain implements Exporter
+{
+    /**
+     * @psalm-var non-empty-list<Exporter>
+     */
+    private array $exporter;
+
+    /**
+     * @psalm-param non-empty-list<Exporter> $exporter
+     */
+    public static function buildWith(array $exporter): self
+    {
+        $exporter[] = new DefaultExporter;
+
+        return new self($exporter);
+    }
+
+    /**
+     * @psalm-param non-empty-list<Exporter> $exporter
+     */
+    private function __construct(array $exporter)
+    {
+        $this->exporter = $exporter;
+    }
+
+    public function handles(mixed $value): true
+    {
+        return true;
+    }
+
+    public function export(mixed $value): string
+    {
+        foreach ($this->exporter as $exporter) {
+            if (!$exporter->handles($value)) {
+                /** @noinspection PhpUnnecessaryStopStatementInspection */
+                continue;
+            }
+        }
+
+        assert(isset($exporter));
+
+        return $exporter->export($value);
+    }
+}